Magnetic Resonance Imaging commonly abbreviated MRI is mainly a qualitative modality. That means that images have an arbitrary scaling and only the intensity differences between tissues, the contrast, are important. Conventional MRI imaging systems mostly use T1-weighted (T1W) and the T2-weighted (T2W) contrast images that utilize differences in the absolute T1 and T2 relaxation, respectively. The values for T1 and T2 relaxation are characteristic for each tissue.
If there is no T1W or T2W contrast in an image it will only reflect the proton density of all tissues; this contrast is called Proton Density Weighted (PDW).
Image contrast is mainly controlled by three MR scanner setting, namely the Echo Time TE, the Repetition Time TR and the Flip Angle α. Equations can be set up to define how much T1- or T2 weighted an image becomes using a certain scanner parameter setting.
Typically a short TR leads to a T1W contrast whereas a long TE leads to a T2W contrast. The combination of a long TR and a short TE leads to a PDW image.
An existing method and system for visualizing MRI images are described in the international patent publication no. WO 2008/082341 A1 which is incorporated herein by reference.
There is a constant desire to improve methods for visualizing MRI images.